The MS-06S Zaku II Commander Type (aka MS-06S Zaku II, MS-06S, S Type) is a mobile suit introduced in Mobile Suit Gundam. One such unit was famously piloted by Char Aznable. 

Developed in response to veteran pilots' request for a high performance unit, the MS-06S Zaku II Commander Type was far more mobile than its predecessor, the MS-06F Zaku II, but was also far more difficult to control. Compared to the F Type, the S Type's vernier nozzles were enlarged, and the output of its main thrusters were increased by 30% while retaining the same size. To make space for the improved thrusters and enlarged propellant tanks, various automatic control systems of the F Type were removed. While this reduced S Type's operability, it also enabled experienced pilots to disable many unnecessary limiters and push the mobile suit to its structural limit.